title: High temperature capture of CO2 on lithium-based sorbents from rice husk ash.
abstract: Highly efficient Li(4)SiO(4) (lithium orthosilicate)-based sorbents for CO(2) capture at high temperature, was developed using waste materials (rice husk ash). Two treated rice husk ash (RHA) samples (RHA1 and RHA2) were prepared and calcined at 800°C in the presence of Li(2)CO(3). Pure Li(4)SiO(4) and RHA-based sorbents were characterized by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, nitrogen adsorption, and thermogravimetry. CO(2) sorption was tested through 15 carbonation/calcination cycles in a fixed bed reactor. The metals of RHA were doped with Li(4)SiO(4) resulting to inhibited growth of the particles and increased pore volume and surface area. Thermal analyses indicated a much better CO(2) absorption in Li(4)SiO(4)-based sorbent prepared from RHA1 (higher metal content sample) because the activation energies for the chemisorption process and diffusion process were smaller than that of pure Li(4)SiO(4). RHA1-based sorbent also maintained higher capacities during the multiple cycles.
authors.affiliation: State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, PR China.
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Guo
authors.forename: Pengfei
authors.initials: P
authors.lastname: Zhao
authors.forename: Fanzi
authors.initials: F
authors.lastname: Wang
authors.forename: Chuguang
authors.initials: C
authors.lastname: Zheng
mesh_terms: D000042:Absorption; D000393:Air Pollutants / Q000302:isolation & purification*; D002245:Carbon Dioxide / Q000302:isolation & purification*; D006358:Hot Temperature; D008094:Lithium / Q000737:chemistry*; D012275:Oryza / Q000737:chemistry*; D059027:Recycling; D017640:Silicates / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D017640:Silicates; D002245:Carbon Dioxide; D008094:Lithium